After selling the Scan Gauge from the USA, and being very successful on the newer WRXs but not on older models i was being asked for something that would work with ALL Subarus..

Well after looking around i have found a neat little Gadget from ECU Datascan

ECUDatascan.com produces a range of products that plug into the diagnostic port of your Nissan (using the Nissan Consult protocol), or Subaru (using the Subaru Select protocol) giving you the ability to view and store a range of engine parameters which is provided by the factory ECU in realtime. These products also include an RS232 slave module, allowing you to connect your factory ECU to your computer, which can then be used for extended datalogging or diagnostics.

The device also has a serial data cable built in so you can connect your laptop to it and log the data.

It also has a peak-hold function, so it will remember the max rpm, pulse width, afm voltage, water temp etc, and store it in memory for recall later (even after power off). The maximum values are shown on the right hand side of the display screen. This is very handy for track days, the odd thrash, and as a tool to see how your friend/mechanic/partner is driving it..